Various processes for preparing meat analogues from generally vegetable protein sources have been proposed in the past. U.S. Pat. No. 2,682,466, U.S. Pat. No. 2,802,737, U.S. Pat. No. 2,830,902 and U.S. Pat. No. 3,142,571 are examples of proposals for preparing meat analogues from such protein sources as soy bean isolate and peanut protein isolate. Another example is GB-A-1418778, which discloses the preparation of a meat analogue starting from a dry mix of proteins, starches and/or gums. All the above processes may be regarded as examples of meat analogue generation.
Roll-refining is a process which is known for producing proteinaceous food products. GB-A-1432278 describes the roll-refining largely on non-meat proteins, although one of its examples, instead of starting with soya protein or casein, begins with "ground meat", soya protein, water and other additives and another of its examples begins with "ground meat", water, casein rennet and other additives.
For the food-stuff manufacturer, who has a choice between either meat protein or non-meat protein sources, it would be preferable in many instances to use meat proteins so that an all-meat product can be prepared. Roll-refining has successfully been applied to raw proteins of vegetable origin, and it would be desirable to apply the same technology to meat proteins.
GB-A-2198623 discloses the roll-refining of fish protein. However, when attempts are made to apply the roll-refining technology to proteins from higher animals (mammals and birds), the process is unworkable since it has generally been found that it is not possible to form a sheet of proteinaceous product from raw mammalian or avian meat unless substantial amounts of additives, such as binding materials are mixed with the meat prior to the process for forming the proteinaceous sheet. Where untreated mammalian or avian meat with no additives has been used, a cohesive sheet is not formed. Sheet products are particularly useful as they may be folded or otherwise used to give a layered structure resembling meat, particularly when cut into chunks.